THE DANGER ZONE

On the 12th play of his first NFL start at left tackle last October, Jaguars rookie Luke Joeckel was assigned to block a basic outside zone running play for Maurice Jones-Drew. At the snap, Joeckel drove three lateral steps into the chest of Rams defensive end Robert Quinn, who was lined up more than a yard to his outside. The two men quickly became locked in a sumo-esque stalemate. As Jones-Drew hit the hole inside Joeckel, defensive tackle Kendall Langford darted from the opposite side and dived across Jones-Drew's back. Langford slipped sideways off Jones-Drew like a cartoon commuter grabbing the door handle of a moving bus, his legs windmilling until his left hip crashed into the bottom of Joeckel's right leg, which was planted in the artificial turf. The run netted one yard.

As other players climbed to their feet, Joeckel sat up and scuttled along the ground with the palms of his hands, moving away from the pile. He knew instantly that he had broken his leg because it had happened before, in much the same way, when he was a sophomore at Arlington (Texas) High. "Pile fell onto the back of my leg," Joeckel recalls. He broke his left tibia then; this time it was his right fibula, and his season was over. "Both times, I had no idea it was coming," says Joeckel. "That's the way it always is when you get rolled up."

That's what they call it: Getting rolled up. The phrase is invoked to describe any incidental harm inflicted on the legs of NFL offensive linemen while they perform their unglamorous trench work. It is what takes place when a giant man has lodged his foot in the earth to block for a teammate on a run or a pass, only to have some part of that play's conclusion spill onto his static limb, snapping it like a dry piece of kindling and/or shredding the ligaments inside. These random acts, often occurring on the periphery of the action, are committed against men—sometimes against teammates—who can't see them coming because they work blind to the mayhem behind them. "It's the only position in all of sports where your back is to the object of the game on every single play," says Howard Mudd, 72, an All-Pro offensive lineman in the 1960s and a respected O-line coach for four decades after that. "You don't see what's happening except right in front of you."

It is one of the most violent acts on a football field, yet in contrast to the most dangerous head blows, late hits or cut blocks, there's no movement to legislate roll-ups out of the game. They are the unintended consequence of heaving nearly 3,000 pounds of flesh, bone and dietary supplements into combat more than 100 times every game. "People see these devastating collisions all over the field where nobody gets hurt and everybody walks away fine," says Patriots offensive tackle Nate Solder. "And then we go down when somebody accidentally falls on us."

INCIDENT REPORT: The Textbook Pile Roll-up

Right guard Chris Snee of the Giants had missed just a single start in eight seasons—three of them as a Pro Bowl selection—when he lined up to block a running play against the Falcons in Week 15 of the 2012 season. As rookie back David Wilson attacked the middle of the line, Snee engaged in a stand-up territorial draw with defensive tackle Corey Peters. But Atlanta defensive end John Abraham steamed off the corner behind Snee, wrapped up Wilson behind the line of scrimmage and bulldogged him into Snee's left hip. Snee buckled backward, walked gingerly off the field and did not return. He started the final two games of the season but underwent surgery in the off-season to repair a torn hip labrum, the first in a series of injuries that hastened Snee's retirement in late July of this year.

Snee, 30 at the time and in his eighth year in the NFL, had played enough football and blocked enough running plays to understand what might happen. "When you're in a stalemate with a guy at the line of scrimmage," says Snee, "and you're not going anywhere, and he's not going anywhere, and the running back hasn't gone by you either, those are clear signs that he's probably right behind you. And in this case, he was."

Every offensive lineman has an acutely developed awareness of the rhythm of a play. As time passes following the snap—four seconds, five seconds—the likelihood of getting rolled up increases. Steelers offensive line coach Mike Munchak, a Hall of Fame guard with the Houston Oilers from 1982 to '93 and the Titans' coach from 2011 to '13, calls it "Spidey sense," in reference to Spider-Man's awareness of impending disaster. "You get that feeling something bad can happen," says Munchak. "You think, Maybe I should get out of here."

With this in mind, they share a mantra: Move your feet. "When [coach] Andy Reid was here," says Todd Herremans, a 10-year veteran guard and tackle with the Eagles, "he would always tell us, 'Keep your feet moving and you'll never get hurt.' " During his rookie season in Jacksonville, Joeckel watched as center Brad Meester, who missed only 15 games in 14 years before retiring after the 2013 season, would run from play-ending piles as if they were giant heaps of skunks. "Not just moving," says Joeckel. "Running." Pat Flaherty has been the Giants' offensive line coach since '04 and constantly reminds the behemoths in his meeting room, "Get your feet out of the hole."

Veteran linemen sense when a play is dead, even if the whistle hasn't blown, and more important, they understand the need to get immediately out of Flaherty's metaphoric hole in the ground. "There are times when you can feel the pile starting to come down on you at the end of a play," says six-time Pro Bowl lineman Logan Mankins of the Patriots, who was rolled up twice in 2011, blowing out his MCL in his left knee and the ACL in his right, yet kept playing. "There are a couple of things you can do at that point. One is to just try to let your leg nearest the pile go limp and not fight the weight. The other is to just go with the pile, just fall with it. Sometimes you get in the most trouble because the guy next to you has made a great block and just blown the whole pile right at you."

None of them admit to dwelling on any of this, except when it's time to dwell on it, in the moment of survival. "If you're thinking about getting rolled up before the play, or during the play," says Snee, "then it's time to walk away from the game."

INCIDENT REPORT: Pursuit Punishment

New England tackle Sebastian Vollmer is typical of NFL offensive linemen: impossibly huge but also shockingly nimble. Vollmer, 30, is 6'8", weighs 320 pounds and moves like a tight end. "He has the kind of size which is rare," coach Bill Belichick told The Boston Globe last winter. "Strength, quickness, athleticism for his size that's pretty special." All of those qualities were on display last October on a second-quarter running play in Foxborough, when Vollmer drove Derrick Shelby, the Dolphins' 282-pound defensive end, from just outside the right hash mark to within two paces of the Pats' bench. Vollmer's block briefly opened a seam for running back Stevan Ridley, but Miami defensive tackle Randy Starks beat guard Dan Connolly and dived at Ridley as he tried to run past. While Vollmer chugged into Shelby, Starks slammed into Vollmer's right leg just as his foot hit the ground, breaking the leg. Vollmer could be heard on the CBS telecast, screaming in pain.

Ten months later Vollmer stood next to the Patriots' practice field and struggled with the moment. "I actually haven't watched it," said Vollmer in soft English, accented with his native German. "I know I was almost to the sideline. I tried to get out of there, but you really don't know what's behind you. Like I said, it's tough. Circumstances. Nobody does it on purpose."

Linemen on both sides of the ball are members of an exclusive, lucrative and dangerous fraternity. The shared peril comes in the waning milliseconds of plays from scrimmage, just when roll-ups are most likely to occur. When Snee was rolled up in Atlanta by Wilson and Abraham, he was fighting Peters, but Snee remembers that Peters pointedly did not finish him off. "He kind of held me up after I got rolled," says Snee. "If he wanted to drive me backward over the pile in a weakened state, he could have done a lot more damage. Probably would have blown out my ACL in addition to the hip. If that were a younger player I was engaged with, it probably would have been a lot worse."

Tacit deals like this one are agreed upon and executed dozens of times in every game. "There definitely comes a time in some plays where it's like, with two veteran guys, O.K., abandon your assignment, save your career," says Herremans. "Usually that's right after the play has been made somewhere else."

Joeckel, just a second-year player, says, "I've noticed a difference between the NFL and college. I'm not saying people take it easy, but I haven't seen many guys who will flip you over the pile in the NFL. There were a lot of those in college." Players taking 70 snaps are also less likely to behave recklessly than situational players getting limited runs. "[Defensive players] who get 10 or 15 snaps are high-motor guys, that's just how they play," says Munchak. "You need to know at all times who is across from you."

Early in his career, Snee developed a habit of breaking stalemates by throwing defenders to the side, and he was only occasionally called for holding. But in his third season he heaved a Bears defender onto the back of teammate Luke Petitgout's legs, breaking Petitgout's fibula. "After that," says Snee, "I eliminated the throwing from my game." But many linemen still toss defenders, and defenders toss linemen. There is often a man—often a teammate—in the landing zone.

INCIDENT REPORT: Collateral Damage

On a running play in the second week of 2012, Eagles second-year center Jason Kelce was expected to execute a reach block on Ravens nosetackle Terrence Cody and help open a hole for LeSean McCoy. Kelce performed the block superbly, but as McCoy raced into the gap, veteran free safety Ed Reed dived at McCoy with his head down. McCoy hurdled the attempt, but Reed's momentum carried his helmet and shoulder into Kelce, collapsing his right knee and blowing out his MCL, while partially tearing his ACL.

"It was kind of a freak one," says Kelce, "because you always want to keep moving, and I was moving, but it just so happened that his helmet hit my knee just as I was planting. You almost never see those injuries, but on that one I did see just a flash of purple at the last second, and I tried to step over the top, but I was just too late."

Mudd was coaching Philadelphia's offensive line at the time and was incensed at Reed for, as Mudd saw it, throwing himself recklessly into traffic. "Ed Reed was getting older and couldn't make the plays he used to make," says Mudd. "So he just dove in low with his head down." Reed did not disagree. "It was bad technique on my part, and I took out the center's knee," Reed told Esquire in the spring of 2013. "Our coach [John Harbaugh] talks to Andy Reid all the time, so I told Coach to send my respects for the center and let him know I didn't mean to hurt him, man. It was just the second game of the year, so he lost his whole season. That one preyed on me, man. I didn't know him personally, but I wanted to let him know that I had the utmost respect for him."

Offensive linemen are divided on whether run plays or pass plays are more perilous. Runs from scrimmage create danger by forcing multiple oversized men into a small space, wrestling with one another while running backs attempt to sprint up their backs for any small slice of yardage. It's fertile ground for roll-ups. But pass plays can be perilous too. Pass rushers wheel outside toward open space on the edge of the formation, building speed and creating torque as they try to shake free. But in lunging for the quarterback, a pass rusher often throws his lower body into blockers protecting different angles in the pocket, especially the tackle blocking the opposite-side edge rusher.

"One game when [quarterback] Donovan [McNabb] was still here, I got leg-whipped about four times," says Eagles left tackle Jason Peters. "You're just trying to hold off your guy, but as you get closer to the quarterback, you get in trouble with guys flying in the other way."

Interior pass blockers face a different issue. Defensive tackles and linebackers routinely run complex stunts, attacking the pocket from fresh angles and forcing offensive guards and centers to adjust their blocking positions. In this improvisational chaos, it's easy to lose spatial awareness and get pushed into pocket traffic. Additionally, says Kelce, "when you're pass-blocking, you really want to be grounded, with a strong wide base. Especially if some guy is bull-rushing you."

INCIDENT REPORT: Pocket Collapse

Jaguars second-year left guard Mike Brewster lined up for a second-and-10 play from the Bills' 33-yard line, an obvious passing down in a meaningless game last December in Jacksonville. Brewster, 6'4" and 305 pounds, controlled Buffalo defensive tackle Corbin Bryant, but from his right, defensive tackle Kyle Williams came free at quarterback Chad Henne. Williams crashed into Henne just after Henne threw the ball, and both quarterback and rusher fell onto Brewster, who remained engaged with Bryant, his back to the action. The combined 528 pounds of Henne and Williams snapped Brewster's left ankle.

"Never saw it coming," says Brewster. "I was just blocking my guy, and they both landed on it. I felt the bone break, immediately, no question. Ideally you keep your feet moving, but in reality there's no way to do that because you're struggling with some guy who weighs 300 pounds. It's a very, very dangerous job. How many jobs can you have where a 300-pound man can fall on you and break your ankle in half?"

Some offensive linemen wear knee braces to prevent—or minimize—roll-up injuries. A smattering of NFL teams have required offensive linemen to wear braces during training camp in recent years, but none have made it mandatory for games. (Many major-college programs require offensive linemen to wear braces in both practices and games.) There are no conclusive medical studies on the effectiveness of braces, which have been in use since Joe Namath first strapped on his bulky Lenox Hill brace in 1965. Offensive linemen are divided: Some swear by the braces' protective qualities, but others complain about their mass and weight.

Joeckel was required to wear them throughout his career at Texas A&M. He doesn't now. "The NFL is too fast a game," he says. "I need that extra step."

In four NFL seasons, Steelers center Maurkice Pouncey has had to miss snaps or games four times because he had been rolled up. He sat out Super Bowl XLV as a rookie after he was inadvertently rolled up from behind by Jets linebacker Bryan Thomas in the AFC championship game, and he was sidelined all last season after an incident in Week 1. He wore braces throughout his career at Florida but abandoned them in the NFL. No longer. "I was so happy to get out of college and throw those braces away," says Pouncey. "This year I put them back on. I'm a true believer."

That would make Kelce a half-believer. He practices without braces, "so I can strengthen the ligaments without support," but will wear them in games for an extra layer of security.

INCIDENT REPORT: Friendly Fire

Pouncey's worst roll-up injury came eight plays into last year's season opener against the Titans. On a rushing play to Isaac Redman, Pouncey was assigned to rub off defensive tackle Sammie Lee Hill, who would then be cut—blocked in the legs—by David DeCastro, a second-year guard who was making his fourth NFL start.

Pouncey sealed off Hill and was in the process of shedding him in pursuit of a linebacker to block when DeCastro threw his body and took out Pouncey's legs instead of Hill's. "David estimated the cut wrong," says Pouncey. "I never saw him. In fact, I just barely remember it because I was in so much pain." The impact tore Pouncey's right ACL and MCL and damaged his PCL and meniscus. He is healthy and back on the field in 2014.

The play underscores the uniquely problematic nature of cut-blocking, some varieties of which were legislated out of the game in the off-season. During an interview at training camp this summer, DeCastro said he would prefer not to execute cut blocks at all. "I've always preferred to just stay up and move the guy," he says. "It's tough to simulate cutting in practice, because it's too dangerous. We use bags, but they don't move. The reality is that I'm just not very good at it. On that play, I didn't even see what happened. My aiming point was bad. I just tried to dive and roll into the nose[tackle], but Pounce was still there. I got all of Pounce and none of the nose." DeCastro paused. "It's difficult to talk about."

DeCastro stood in a grove of trees outside the Steelers' summer dining hall and took stock of his occupation. He was rolled up and tore two ligaments in his right knee during a 2012 preseason game, and missed most of his rookie season. "Honestly, I think it's amazing more [linemen] don't get hurt," he said. "There's a lot of people pushing, shoving and throwing each other around." He shook his head, then shrugged. "It's a random, violent game." Violent everywhere on the field, but nowhere more random than in the small space where linemen collide and giant men hope only to be spared.

It is one of the most violent acts on a football field, yet there's no movement to legislate roll-ups out of the game.

None of the offensive linemen will admit to dwelling on any of this, except when it's time to dwell on it, in the moment of survival.

[The following text appears within a diagram. Please see hardcopy or PDF for actual diagram.]

Mitchell Schwartz

BENCH PRESS: 23 √ó 225 LBS.

Ryan Kerrigan

260 LBS.

Brian Orakpo

ONE OF NFL'S STRONGEST LINEBACKERS BENCH MAX: 515 LBS.

Joe Thomas

KNEE BRACE; TORE ACL IN 2006

John Greco

Joel Bitonio

COMBINED WEIGHT: 623 LBS.

PHOTOPhotograph by Al Tielemans Sports Illustrated

CRASH COURSE As Browns left tackle Joe Thomas (73) knows, a planted leg is one that can get rolled up.

PHOTOTOM GANNAM/AP

A LA CART Joeckel (above) broke his leg for the second time; Snee (right) tore his labrum and was forced to retire at 32.

PHOTOJIM O'CONNOR/USA TODAY SPORTS

[See caption above]

PHOTOCJ GUNTHER/EPA

OUT OF ACTION Vollmer (76) and Kelce (62) both missed significant time after getting hurt on run plays.